Temperature responsive firing mechanism



Feb. 13, 1962 I J. M. HARDESTY 3,020,845

TEMPERATURE RESPONSIVE FIRING MECHANISM Filed Nov. 4, 1960 2 Sheets-Sheet 1 INVENTOR nfi-% Q ATTORNEY 2 Sheets-Sheet 2 J. M. HARDESTY TEMPERATURE RESPONSIVE FIRING MECHANISM Feb. 13, 1962 Filed Nov. 4, 1960 i--- INVENTOR I ljM/ /q/wss T Isa/j W ATTORNEY a m snZstS i Eatented Feb. 1 1962 3,020,845 TEMPERATURE RESPONSIVE FG MECHANISM Jules M. Hardesty, Rte. 2, Box 22, Rivesville, W. Va. Filed Nov. 4, 1960, Ser. No. 67,308 7 Claims. (Cl. 102-70) This invention relates to a firing mechanism actuated automatically if the temperature drops to a predetermined extent to effect detonation by impact of an explosive element. 7

More particularly, it is an aim of the present invention to provide a mechanism which maybe utilized for detonation of an explosive element to ignite fuel contained in a burner, such as a smudge pot, whereby such ignition of the burner fuel can be accomplished automatically when heat from the burner is required.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description'of the drawings, illustrating a presently preferred embodimentth'ereof, and wherein:

FIGURE 1 is a horizontal sectional view, partly broken away, taken substantially along the line 11 of FIGURE 2, of the firing mechanism;

FIGURE 2 is a longitudinal substantially central sectional view, partly inside elevation thereof;

FIGURE 3 is a cross sectional view of the firing mechanism, taken substantially along the line 33 of FIG- URE 2;

FIGURE 4 is a cross sectional view through a part of the firing mechanism, taken substantially along a plane as indicated by the line 4-4 of FIGURE 2, and

FIGURE 5 is a fragmentary horizontal sectional view, taken substantially along the line 5-5 of FIGURE 2.

Referring more specifically to the drawings, the temperature responsive firing mechanism in its entirety and comprising the invention is.designated generally 7 and includes a frame, designatedgenerally 8. The frame 8 includes a top wall 9, a bottom wall 10, an end wall 11, a transverse wall 12 and longitudinal walls 13. The walls 11, 12 and 13 are secured to the top and bottom walls by fastenings 14. The bottom wall 10, as seen in FIG- URE 2, has an upwardly offset end portion 15 which is located remote from the end wall 11, and the walls 12 and 13 are located between said end portion 15 and an end portion 16 of the top wall 9. The transverse wall 12 is located inwardly with respect to the longitudinal walls 13, as best seen in FIGURE 1, so that the walls 12 and 13 combine with the wall portions 15 and 16 to form a chamber 17 which opens outwardly of the end of the frame formed by said wall portions.

A temperature responsive unit, designated generally 18, such as a waflle type thermostat, is disposed in the frame 8 near the end wall 11 and is anchored by nut and bolt fastenings 19 to the bottom wall 10. The anchoring fastening 19 projects from and is secured to an underside of the expansible and contractile portion 20 of the unit 18 for anchoring said underside of the portion 20 immovably to the frame 8. A threaded stud 21, of the unit 18, is fixed to and extends upwardly from the opposite end or upper side of the portion 20, and an internally threaded sleeve 22 is threadedly mounted on the stud 21 and is adjustable toward and away from the portion 20. The sleeve 22 extends loosely through an opening 23 in the top wall 9, and is provided with a collar or enlargement 24 which is disposed substantially below the top wall 9.

A pair of transversely spaced bearing posts 25 extend upwardly from the top wall 9, between the chamber 17 and the thermostat 18. The posts 25 are preferably formed by struck-out portions of the wall 9 and provide a support for a shaft 26 which extends therethrough. A

hammer, designated generally 27, includes a lever arm 28 having downturned flan-gas 29 having aligned apertures 30 at one end thereof which engage turnably on the shaft 26. A spring 31, formed from a strand of wire, has portions 32 wound loosely on the shaft 26, an intermediate portion 33 which extends from adjacent ends of the spirally wound portions 32 and which bears against an underside of the lever arm 28 at a point spaced from the shaft 26, and terminal portions 34 which project from remote ends of the wound portions 32 and which engage in notches 25' of the top wall 9, formed by posts 25, and are anchored to said wall 9, as seen in FIGURES 1 and 3, for maintaining tension on the spring 31 so that the portion 33 thereof is biased to swing clockwise, as seen in FIGURE 2, for swinging the hammer 27 from its position of FIGURE 2 in a clockwise direction, as indicated by the arrow tipped lines 35. The hammer 27 includes a hammer head 36 which is fixed to and projects from the side of the lever arm 28, located opposite to the side thereof engaged by the spring portion 33, which hammer head is located remote from the shaft 26.

The lever arm 28 has a downturned detent portion 37 at A sear 43, formed from an elongated substantiallyflat rnetal strip, has a flared end forming a head 44 which is provided with an outwardly opening lower notch 45 and an outwardly opening upper notch 46. The bar portion 40 of the bracket 39 fits loosely in the enlarged inner portion of the lower notch 45 and a part 47 of the head 44 extends through the lower slot 41. The sear 43 is thus pivotally connected to the bracket 39 for vertical rocking movement about the bar 40, and said sear extends longitudinally of the frame 8, from the bracket 39, in a direction away from the sleeve 22 and opening 23. The slots 45 and 46 thus open toward the sleeve 22 and the portion of the head 44, disposed above the upper slot 45, defines a dog or pawl 48 which is engageable in the opening 38 for latching the hammer 27 in a cocked position, as seen in FIGURE 2, as will hereinafter be more fully described. The part 49 of the head 44 is disposed for rocking movement in the bracket notch 42 to prevent the sear 43 from rocking laterally to any appreciable extent relative to the bracket 39.

A sear latch, designated generally 50, comprises -a strip of metal which is folded lengthwise to provide corresponding side walls 51 and a top wall 52. One end of the searlatch 50 fits loosely between a pair of posts 53 which are struck-up from the top wall 9, and a shaft 54 extends through the posts 53 and the side walls 51;

for pivotally mounting the sear latch for up and down swingingmovement relative to said posts. The posts 53 are located between and adjacent the posts 25 and in alignment with the bracket 39, and the sear latch 50 extends from its pivot 54 toward the bracket 39, as seen in FIGURE 1, and engages over the arm portion 55 of the sear 43. The top wall 52 has an elongated opening 56 therein, and the end of the top wall 52, located adjacent the pivot 54, is provided with a depression forming a longitudinally extending upwardly opening groove or channel 57 which opens into one end of the opening 56 at its inner edge portion 58. The end of the sear arm 55, located remote from the head 44, is rounded on its upper side, as seen at 59, to provide a cam surface. The side walls 51 have laterally extending outwardly projecting aligned studs or pins 60 which are spaced from the ends thereof.

A pair of hangers 61 are struck from the top wall 9 and are disposed substantially in transverse alignment with one another and with the bracket 3?. A shaft 62 extends through the hangers 61 and is supported thereby. The shaft 62 extends loosely through upstanding side flanges 63 of a lever 64 forming a trigger actuator, which is thus 'pivotally supported intermediate of its ends for vertical rocking movement. Side flanges 65 of a lever 66, forming a trigger, fit loosely between the side flanges 63, and the shaft 62 extends loosely through said side flanges 65, at one end of the trigger 66, for pivotally mounting the trigger thereon. Arms 67 form upwardly extending curved extensions of the other ends of the flanges 65 and extend upwardly through transversely spaced openings 66 of the top wall 9. The arms 67 have heads 69 at their upper ends, which are located above the plane of the top wall 9 and beneath the pins or studs 69, as seen in FIGURES l and 2. p The trigger 66 extends from its pivot 62 in a direction awayfrom the thermostat 13', The side flanges 63 of the trigger actuator, at the ends thereof disposed remote from the trigger 66, have inwardly extending aligned lugs 76 as bestseen in FIGURE 5, which loosely straddle the sleeve 22 beneath the collar 24, and the collar 24 is adapted to bear on said lugs 70 when the thermostat 18 is contracted, as will hereinafter be described. The lugs 70 are disposed beyond an adjacent end of a bottom wall 71 of the trigger actuator 64.

The bottom wall 71 has an insert 72 provided with a threaded bore 73. A screw 74 is threaded upwardly through the bore 73 and is located on the opposite side of the pivot 62 from the lugs 70 and bears against a part of the bottom plate 75 of the trigger 66. A compression spring 76 i disposed on the screw 74 between the insert 72 and the screw head 74 and is disposed under sufficient compression to retain the screw '74 in different adjusted positions in the bore 73.-

An anvil block 77 fits slidably in the chamber 17 and has an upwardly opening socket 78 which aligns with an opening 79 in the top wall portion 16, when the block 77 is seated in the chamber 17, abutting the transverse wall 12, as seen in FIGURES 1 and 2. The upper portion of the anvil block 77 has a groove 80 which opens into the socket 73 and outwardly of the outer end wall fll of said block. The groove 80 has an enlarged portion 82 spaced from the ends thereof.

A bore 83 extends through the block 77, below the socket 73 and groove 80, and has one end opening outwardly of the end wall 81 and an opposite end which aligns with an opening 83 of the transverse wall 12. A red 84 extends loosely through the opening 83' and through the bore 33 and has a diametrical bore 85 adjacent one end thereof in which a cotter pin 86 is detachably mounted. The cotter pin 66 normally bears against the end face 81 of the block 77. A compression spring 87 is disposed loosely around the pin 84 between its head 83 and the transverse wall 12 for normally retaining the block '77 seated in the cavity or chamber I7.

An end of a conventional fuse 89 engages in the groove 80 and a percussion cap or other detonator 96, connected to said fuse end, seats in the anvil socket 73. A clan1ping ring 91 which secures the percussion cap 90 to said fuse end seats in the enlargement d2 of the groove Sit to prevent the fuse end from being pulled out of the groove and disengaged from the percussion cap. The other end of the fuse 89 may be connected to an incendiary tube 92 which is supported by the stake 913, which can be driven in the ground, above a part of a fuel containing receptacle 94 of a burner, not otherwise shown, such as a smudge pot, so that when the percussion cap 9% is detonated the fuse 89 will be lighted to ignite the incendiary tube which in turn will ignite the fuel 95 contained in the receptacle 94.

The hammer 27 is shown in FIGURE 2 in a cocked position held by the sear dog 48 engaging the hammer detent 37. A reduction in temperature will cause contraction of the thermostat portion 20 to exert a downward pull on the rod 21 and sleeve 22. As the collar 24- moves downwardly with the sleeve 22, the trigger actuator 64 will be rocked about the pivot 62 in a counterclockwise direction so that the screw 74 will press upwardly on the trigger bottom 75 to cause the trigger 66 to rock counterclockwise on the pivot 62. As the trigger 66 is thus rocked, the arm heads 69 will move upwardly into engagement with the pins 60 and will thereafter swing the sear latch 50 in a clockwise direction about its pivot 54 and relative to the sear 43. As the sear latch 50 swings upwardly the edge 58 thereof will move clockwise until it clears the rounded sear end 59 to thus release the sear 43. When this occurs, the tension of the spring 31 will cause said sear to rock clockwise relative to the bracket 39 to disengage the sear dog 48 from the detent 37, thereby releasing the hammer 27 which will be swung by the tensioned spring 31 through the are as defined by the arrow tipped lines 35, for causing the hammer head 36 to pass through the opening 79 into the socket 78 of the anvil 77 to forcibly strike and detonate the percussion cap 96 to eifect lighting of the fuse 89.

To re-cock the firing mechanism 7, it is only necessary to manually swing the hammer 27 counterclockwise back toward its cocked position of FIGURE 2. As the hammer 27 moves slightly past its position of FIGURE 2, the lower end of the detent 37 will strike the upper edge of the sear head portion 49 to exert a downward force on said portion for rocking the sear counterclockwise about the bracket 39 and back toward its position of FIGURE 2. As the sear portion 55 swings upwardly its cam edge 59 contacts the underside of the edge 58 for causing the sear latch 50 to swing upwardly about its pivot 54 in a clockwise direction until the cam edge 59 clears the edge 58, whereupon the sear latch 50 swings downwardly or counterclockwise by gravity to position the edge 58 thereof and a part of the grooved top wall portion 57 beneath the sear end 59, to thereby re-latch the sear in its operative position. This rocking movement of the sear 43 in a counterclockwise direction back to its operative position, causes the sear pawl 48 to move from right to left into the detent opening 38 and thus into engagement with the detent 37 for holding the hammer 27 in its cocked position. The edge portion 96 of the top wall 52, located most remote from the pivot 54, rests upon a portion of the upper edge of the sear 43, near the head 44, to provide a unique suspension wherein the overlapping free ends of the sear and sear latch, which are located between the pivots of the scar and sear latch, interengage with one another so that each supports the other in a raised position.

It will also be readily apparent that two adjustments are provided, one by the sleeve 22 and the other by the screw 74, to vary the amount of movement of the thermostat 18 required to rock the trigger actuator 64 and trigger 66 sufiiciently to move the sear latch to a position for releasing the sear.

To reload the firing mechanism 7, pressure is applied to the head 38 for displacing the rod 84 from left to right of FIGURE 2. so that the anvil 77 can be moved surficiently from the chamber 17 to expose the groove and a part of the socket 78 in order that the fired percussion cap 96 and fuse end can be removed from the anvil block 77 and replaced by the end of a new fuse and percussion cap. If pressure is released on the head 88, the compressed spring 87 will return the anvil block 77 to its fully seated position in the chamber 17, as seen in FIGURES l and 2.

Various modifications and changes are contemplated and may be resorted to, without departing from the function or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. A temperature responsive firing mechanism comprising a frame, a hammer, means swingably mounting said hammer on the frame, an anvil mounted in the frame, a spring urging said hammer to swing toward and into engagement with the anvil for detonating an element supported by the anvil, latch means supported by said frame and engaging the hammer for releasably retaining the hammer in a retracted, cocked position against the tension of said spring, a temperature responsive unit secured to said frame and including a movable part, and a latch actuator pivotally supported by said frame and including a part disposed to be engaged and actuated by said movable part of the temperature responsive unit in response to a temperature change, and another part disposed to engage said latch means for moving the latch means to a position to disengage the hammer when said latch actuator is moved by the temperature responsive unit.

2. A temperature responsive firing mechanism as in claim 1, said anvil comprising a block having an upwardly opening socket for containing said element to be detonated, said frame having a chamber opening outwardly of an end thereof and containing said anvil, said frame having a top wall provided with an opening registering with the anvil socket, spring means releasably retaining said anvil in the frame, and said spring means including a manually engageable part for movement of the anvil outwardly of the frame for removal and replacement of a fired detonator element.

3. A temperature responsive firing mechanism as in claim 2, said anvil including means opening into said socket and outwardly thereof for releasably anchoring a fuse end, connected to the detonator element, to the anvil.

4. A temperature responsive firing mechanism as in claim 1, said latch means including a sear and sear latch having remote pivotally mounted ends and interengaging free ends disposed between the sear pivot and sear latch pivot, said latch actuator engaging said sear latch, when moved by the temperatures responsive unit, for rocking the sear latch for disengaging it from the sear for relaasing said sear from a holding position relative to the hammer.

5. A temperature responsive firing mechanism as in claim 4, said sear having a part disposed to be engaged by a part of the hammer when the hammer is moved to a retracted position for rocking the sear to a position for re-latching the sear and the sear latch for holding the hammer in a cocked position.

6. A temperature responsive firing mechanism as in claim 5, said first mentioned part of the latch actuator comprising a lever pivotally mounted at a point spaced from the ends thereof and having one end engaging said movable part of the temperature responsive unit, said last mentioned part of the latch actuator comprising a trigger pivotally mounted at one end thereof and having an opposite free end engageable with the sear latch, an element adjustably mounted in the other end of said lever and engageable with an intermediate portion of the trigger for effecting rocking movement of the trigger in one direction with said lever after a predetermined initial rocking movement of the lever in said direction relative to the trigger, to vary the extent of movement of said movable part of the temperature responsive unit necessary to effect release of said latch means.

7. A temperature responsive firing mechanism as in claim 1, and means for manually adjusting said movable part of the temperature responsive unit relative to the latch actuator to vary the extent of movement of said part required to effect release of the latch means.

References Cited in the file of this patent UNITED STATES PATENTS 1,962,387 Brubaker June 12, 1934 2,075,813 King Apr. 6, 1937 2,482,135 Winkle Sept. 20, 1949 2,487,789 Carr et a1 Nov. 15, 1949 2,965,005 Reed Dec. 20, 1960 

